Dicyanopiperazine is a useful compound due to its active cyano-groups. It is an intermediate in the manufacture of biguanide antibiotics as described in British patent specification No. 1,309,832 which also includes descriptions for the synthesis of substituted cyanamides by the reaction of secondary amines with cyanogen halides in the presence of ammonia according to Equation (I): ##STR1## As pointed out therein, problems arise in this reaction due to the well known tendency of ammonia and amines to react with cyanogen halides to form cyanamides according to the Equation (II): EQU CNCl+NH.sub.3 .fwdarw.CN.NH.sub.2 +HCl (II)
The yields according to the process described in these references are only in the range 87 to 93% and require the use of ammonia. The ammonium chloride by-product presents disposal problems.
It is an object of this invention to provide a process for the preparation of dicyanopiperazine in high yield in the range 97 to more than 99% and of high purity of at least 96%. It is further object to provide a process that utilizes less expensive reaction components and is conducted in a medium wherein the final by-products to be disposed are ecologically acceptable.